Ain't nobody doing a anything?

[admin_jsfisher]

I, for one, am just a rank amateur willing to waste lots money on an interesting hobby. Someday I may actually produce a hologram worth showing people, but in the meantime I'm enjoying "just trying things."

This is where I'm at too. Just trying stuff. For his science project, my son made diffraction gratings from Ed Wesley's 7 single beam projects, where he varied the angle between mirror and plate... his results are pretty cool.

Ed is a good guy. I'm sure if you are ever up his way with your son, he'd be glad to meet with you both and show you around his lab.

[Martin]

There was a discussion (sometime ago, now) about using ferro-cyanide chemistry in place of dichromates.

You may be mixing apples and oranges. Martin from Polygramma, came up with an emulsion that involved ferro-cyanide, I can't remember the exact emulsion because it was some years ago; if Martin is still reading these pages, perhaps he could chime in with the emulsion. Martin did not have a blue laser, so we coated some plates with his emulsion formulation, shot a few holograms, and sent the results to him.

Pleased to hear there still is some interest in the ferric gelatin (FEG) process.
The ferric components that produced bright holograms were:
FERRIC AMMONIUM CITRATE (the "green" one only!),
FERRIC AMMONIUM OXALATE,
FERRIC CHLORIDE

Contrary to the Herschel's Cyanotype ("Blueprint") process there is no ferricyanide involved. It's based on the reaction of photo reduced Fe2 (ferrous) with hydrogen peroxide. The choice of gelatin seems to be crucial.

I'd like to resume my experiments. The main obstacle is that my 405nm diode is no longer working. So I'm looking for a new violet-blue laser (400 - 450nm).

[John Klayer]

I shot several holograms in a cave this afternoon (Oct 10) with the new single fiber set up. Maybe I should have tested it in the lab first as I had some problems with alignment. What I did was send a beam thru a TosLink fiber then split it with a thin plate beam splitter with the transmitted part going to a convex mirror to bounce back to the plate as the reference and the reflected part hitting a reflective diffuser to spread out for object illumination. I just got home a little past midnight and I have to go to work in the morning so I'll be developing the plates when I get home after work tomorrow.

[John Klayer]

I finally got the shots from Sunday developed. The images are weak. I went with what I felt was good exposure times instead of what I calculated. Sometimes I do dumb stuff.

[Din]

Sometimes instinct is better than calculation, and sometimes not. Nothing dumb about it. Of course, you should always use your instinct to check your calculation.

[Din]

We went to Girl Tech 2016 again this year where we demonstrated optics and optical principles to young girls, 5th to 8th grade.

As I mentioned a few posts back, these are pictures of some of the girls at our demo. We set up a few holograms, and a few demonstrations. For the demonstrations we had:

Polarisation:
We taped several layers of sticky tape on a clear, transparent plastic surface. We then showed them that if you put a polariser behind the plastic sheet, and one in front, then, when you hold the sheet against the sun and rotate the polariser, a series of coloured bands appear. We explained that this is called Birefringence.

Writing with light:
We fixed a fiber optic cable onto a uv laser pointer. We also coated a sheet of stiff cardboard with glow-in-the-dark paint. We then invited the girls to use the end of the fiber to write on the surface. Where they "wrote", they could see an outline of their drawing as it glowed, then faded.

Coloured Shadow Box:
We placed red, green and blue leds, each with their own switch. We then asked the girls to put their hands into the shadow box and succesively turn and turn off individual lights and see the colours of the resultant shadows.

So, here, as promised, some of the pictures from our participation in Girl Tech 2016

Girl_Tech_2.jpg (1.94 MiB) Viewed 4723 times

Girl_Tech_3.jpg (53.34 KiB) Viewed 4723 times

Girl_Tech_4.jpg (48.16 KiB) Viewed 4723 times

[Din]

Girl_Tech_5.jpg (36.69 KiB) Viewed 4723 times

Girl_Tech_6.jpg (53.8 KiB) Viewed 4723 times

Girl_Tech_7.jpg (37.65 KiB) Viewed 4723 times

[Sergio]

We are adjusting the polymer formulation for a true color 450/532/650 photopolymer. This is a client requirement and probably will not be sell as a commercial film.

The industry is firmly stick on photoresist embossed security films and we still can not change the paradigm. So a l.ot of investment is necessary to introduce the embossed volume hologram. Some volume holograms are already on money but it depends greatly on political power to manage this..

Besides the extremely weak amateur business, the display holography marketing actually isn't profitable... so rest the specialized uses of holograms in scientific projects, "that technical holography is doing pretty well" as Dinesh said is confirmed by me and deal even with non-imaging optics with lot of research and calculation.